The present invention relates to the field of equipment which can be used by industrial robots for gripping workpieces or assemblies being processed or assembled.
Equipment of this type is used, for example, in the automobile industry for supporting assemblies or subassemblies of bodies of motor vehicles during welding operations and/or assembly operations of various kinds, which are typically performed with automatic welding devices and/or assembly devices.
In the above applications, there exists, of course, the need to guarantee that the industrial robot will support the workpiece or assembly, on which it is necessary to operate in a rigorously pre-determined precise position. Gripping equipment used by robots for the aforesaid purposes present, of course, a part designed for being connected directly to the robot and a plurality of reference and positioning elements designed to engage with the workpiece or the assembly that is to be supported, which guarantee that the latter will find itself in a pre-determined position with respect to said reference and positioning elements. Obviously, it is equally essential that the structure of the gripping equipment should present a rigorously defined rigid geometry, which will guarantee that the various reference and positioning elements will find themselves in rigorously pre-determined spatial positions with respect to the part of the equipment that is directly connected to the robot.
In the past, for the purpose of guaranteeing a rigid and precise geometry of the equipment there has usually been adopted gripping equipment having a structure made of metal elements welded together. If, on the one hand, said solution might guarantee a structure with a rigorously defined geometry, on the other hand it entails considerable problems when it is necessary to reproduce the same starting geometry, for example, after possible damage of the structure following upon a collision with an external body during use of the equipment by the robot. Obviously, in such an eventuality it is neither possible to guarantee that the deformed welded structure will be brought back again to the initial geometry nor to certify that the structure will go back to the initial geometry in a simple and rapid way.
When an attempt is made to solve the aforesaid problem by adopting for the gripping equipment a structure consisting of elements connected to each other in a separable way, the new problem arises of guaranteeing that the assembled structure will have a rigorously precise and pre-determined geometry and above all that said geometry will be reproducible, for example after a deformation or failure of one or more of its components following upon an accidental collision, in a way that is simple, rapid and easily certifiable.
The purpose of the present invention is to provide an effective and efficient solution to the aforesaid problem.
In order to achieve said purpose, the subject of the invention is a piece of equipment which can be used by an industrial robot for gripping workpieces or assemblies being processed or assembled.
Thanks to the aforesaid characteristics, the reticular structure with circular bars which supports each reference or positioning element may be assembled in an easy and rapid way, guaranteeing rigorous respect of the desired geometry.
Thanks to the characteristics indicated above, the equipment according to the invention is able to provide an efficient solution to all the problems set forth above. The fact that it is made up of modules connected together in an uncoupleable way obviously enables easy restoration of the modules which are deformed or anyway damaged, for example following upon accidental collisions, without there existing the need for replacing the entire structure. The use of components consisting of modules in the form of metal sectional elements simplifies and rationalizes assembly of the structure of the equipment. Finally, the pre-arrangement at pre-determined intervals of length of the aforesaid pairs of notches in the slits of the sectional elements, for the engagement of the guide bushings of the connection screws, provides a simple and at the same time extremely efficient means for guaranteeing convenient repeatability of the geometry of the structure. In practice, in fact, the various pairs of opposed notches define along the external surface of the sectional element a series of seats set at equal distances apart from one another, which can be used for positioning the connection screws. The said seats therefore provide in the sectional element a sort of indexing that enables for the user immediate identification of the point of connection, which is thus uniquely defined by counting the number of seats along the sectional element starting from one end of the sectional element up to the seat in which it is desired to engage the connection screw. The above basic principle can be used in all the connections between the sectional elements which make up the structure of the gripping equipment, as well as in the connection of the sectional elements with a component, typically a plate, designed to be connected to the industrial robot.